Refactored byte[] arrays in GifConstants type

src/ImageSharp/Formats/Gif/GifConstants.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors and contributors.
 // Licensed under the Apache License, Version 2.0.
 
+using System;
 using System.Collections.Generic;
 using System.Text;
 
@@ -21,11 +22,6 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// </summary>
         public const string FileVersion = "89a";
 
-        /// <summary>
-        /// The ASCII encoded bytes used to identify the GIF file.
-        /// </summary>
-        internal static readonly byte[] MagicNumber = Encoding.ASCII.GetBytes(FileType + FileVersion);
-
         /// <summary>
         /// The extension block introducer <value>!</value>.
         /// </summary>
@@ -51,11 +47,6 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// </summary>
         public const string NetscapeApplicationIdentification = "NETSCAPE2.0";
 
-        /// <summary>
-        /// The ASCII encoded application identification bytes.
-        /// </summary>
-        internal static readonly byte[] NetscapeApplicationIdentificationBytes = Encoding.ASCII.GetBytes(NetscapeApplicationIdentification);
-
         /// <summary>
         /// The Netscape looping application sub block size.
         /// </summary>
@@ -101,6 +92,26 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// </summary>
         public static readonly Encoding Encoding = Encoding.ASCII;
 
+        /// <summary>
+        /// Gets the ASCII encoded bytes used to identify the GIF file (combining <see cref="FileType"/> and <see cref="FileVersion"/>).
+        /// </summary>
+        internal static ReadOnlySpan<byte> MagicNumber => new[]
+        {
+            (byte)'G', (byte)'I', (byte)'F',
+            (byte)'8', (byte)'9', (byte)'a'
+        };
+
+        /// <summary>
+        /// Gets the ASCII encoded application identification bytes (representing <see cref="NetscapeApplicationIdentification"/>).
+        /// </summary>
+        internal static ReadOnlySpan<byte> NetscapeApplicationIdentificationBytes => new[]
+        {
+            (byte)'N', (byte)'E', (byte)'T',
+            (byte)'S', (byte)'C', (byte)'A',
+            (byte)'P', (byte)'E',
+            (byte)'2', (byte)'.', (byte)'0'
+        };
+
         /// <summary>
         /// The collection of mimetypes that equate to a Gif.
         /// </summary>

src/ImageSharp/Formats/Gif/GifEncoderCore.cs

@@ -238,7 +238,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// </summary>
         /// <param name="stream">The stream to write to.</param>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private void WriteHeader(Stream stream) => stream.Write(GifConstants.MagicNumber, 0, GifConstants.MagicNumber.Length);
+        private void WriteHeader(Stream stream) => stream.Write(GifConstants.MagicNumber);
 
         /// <summary>
         /// Writes the logical screen descriptor to the stream.

src/ImageSharp/Formats/Gif/Sections/GifNetscapeLoopingApplicationExtension.cs

@@ -29,7 +29,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
             buffer[0] = GifConstants.ApplicationBlockSize;
 
             // Write NETSCAPE2.0
-            GifConstants.NetscapeApplicationIdentificationBytes.AsSpan().CopyTo(buffer.Slice(1, 11));
+            GifConstants.NetscapeApplicationIdentificationBytes.CopyTo(buffer.Slice(1, 11));
 
             // Application Data ----
             buffer[12] = 3; // Application block length (always 3)